Definition of "PCA"

PCA

proper noun
1. (linguistics) Abbreviation of Proto-Central Algonquian.
2. (US, law) Abbreviation of Posse Comitatus Act. The U.S. law called "Posse Comitatus Act", 20 Stat. 152 aka 18 U.S.C. § 1385
3. (US, politics, historical) Initialism of Progressive Citizens of America.
  Quotations
  The PCA was demonstrably a Communist-front organization, and most of the Hollywoodites whom it rallied to its support were members of the Communist Party, some of them having been notorious as such for many years.
  1956, United States. Congress. House. Committee on Un-American Activities, Hearings, page 171
noun
plural PCAs
1. (aviation) Abbreviation of propulsion controlled aircraft (system/unit), an aircraft with a control system with two or more engines arrayed abreast, allowing descent, ascent, turns by adjusting the throttle control to the engines (sometimes used attributively).
2. (statistics) Abbreviation of principal components analysis.
3. (medicine) Abbreviation of patient-controlled analgesia; palliator.
4. (anatomy) Initialism of posterior cerebral artery.